Balance slide-valve



(No Model.)

G. T. SNOWDEN.

BALANCE SLIDE VALVE.

No. 326,800. Patented Sept. 22, 1885.

UNiTnn STATES PATENT @rrrca GEORGE T. SNOYVDEN, OF PITTSBURG, PENNSYLVANIA.

BALANCE SLIDE-VALVE.

JPECIFICATION forming part of Letters Patent: No. 326,0O, dated September 22, 1885.

Application filed June 2, 1885. (No model.)

To aZZ whom it may concern.-

Be it known that I, GEORGE T. SNOWDEN, of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented ,certain new and useful Improvements in Balance Slide-Valves; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

This invention has relation to certain im provements in balance slide'valves, wherein the construction and arrangement is such as to relieve the slidevalves of steam-engines from the pressure of steam upon the back of the valve.

The object of this invention is to provide a mechanism which may be readily applied to the valves of locomotive-engines, as well as to others, and which, while being simplein construction and economical, will operate effectively and allow the valve to perform its work unrestrained.

In Letters Patent of the United States No. 6%441, granted the 22d day of January, 1867, is shown and described a slide balancing mechanism which I have adopted as the basis of my present improvements. In said patent the essential elements of the balancing mechanism consist of a plate resting on the back of the valve and formed with a short internallybeveled cylinder, which encircles a cylinder or boss depending from the under side of the steam-chest cover. An externally beveled packing-ring is interposed between the beveled cylinder and the boss for the purpose of making the joints steam-tight. As the plate rises and falls in adapting itself to the pressure on the valve it is intended that the cylinder on said plate shall slide upon the tapered or beveled surface of the packing-ring. I have found, however, in practice that when the packing-ring is beveled on its outer surface, as shown in the patent, it has a tendency to bind and wedge itself in its seat, and there fore interfere with the free movement of the balancing-plate.

My present invention contemplates the remedying of this defect, and accordingly consists, primarily, in constructing the pack ing-ring with its inner surface beveled, while its outer surface remains true or perpendicular to the surface of the balancing-platethat is, perfectly cylindrical.

My invention furthermore consists in making the inner boss or cylinder separate and distinct from the valve-chest cover and securing it in place by means of a bolt passing through the cover.

My invention finally consists in the provision of an elliptic spring or springs, which, being fastened to a pin passing through the center of said bolt and made adjustable thereby, press against or upon the upper surface of the balancing plate, and tend to keep the balancing-plate in position when the steam is shut off.

Referring to the accompanying drawings, wherein Figure 1 is a longitudinal section of a valve provided with my improvement, and Fig. 2 a top view of the same, the letter A designates the valve, which may be of any ordinary or suitable shape, with its back faced off true, upon which rests the plate B, said plate having upon its upper side the short cylinder 0, whose inner and outer surfaces are parallel.

Attached to the under side of the valvecover A is a block or boss, F, consisting of the base-platef and the flaring wall or flange f. This block is secured to the cover A by means of a central bolt, F, threaded to receive a nut, F. This bolt is bored through centrally and tapped to receive a set-screw, G, upon the lower end of which are fastened one or more elliptic springs, H, the ends of which rest on the upper surface of the plate B, as shown. This pin is headed, as shown at g, and provided with ajan1-nut,g, which secures the pin or set-screw and allows it to be adjusted to regulate the pressure of the spring.

By constructing the packing-ring E with its inner surface beveled, and correspondingly tapering the flangef, the packingring has a free and unobstructed play, moving with the plate B, and avoiding all such tendency to wedge or bind as obtained in the construction shown in the patent.

The operation of the devices described is substantially as described in the patent and need not be repeated.

I have shown a skeleton form of valve; but

the balancing mechanism is equally adapted to valves having closed backs.

What I claim, and desire to secure by Letters Patent, is-

5 1. The combination of the packing-ring E,

havingits inner surface beveled, with the plate well B, having the cylinder 0, and with the box or' boss F, having its outer flanged portion flaring or tapered to correspond with the bevel 10 of the packing-ring, substantially as described. 2. The box or boss F, having tapered flange f, and made separate and distinct from the valve-chest cover, in combination with the inter'nally-beveled packing-ring E, the plate B,

having cylinder 0, the bolt F, bored centrally and carrying the set-screw G, and the spring or springs H, substantially as described.

In testimony that I claim the foregoing as my own I have hereto affiXed my signature in presence of two witnesses.

GEORGE T. SNOWDEN. Witnesses:

A. A. MOORE, O. L. STRAUB. 

